1. Field of the Invention
The present invention is directed to foam insulation, and more particularly to a method of making non-flammable thermal insulation foam from water soluble alkali metal silicates and organic materials. The invention is also directed to a method of making nonflammable foam panels made from water soluble alkali metal silicates and filler additives.
2. Brief Description of the Related Art
Thermal insulation is known for use in houses, buildings, pipes, ductwork, and many other applications. The best known thermal insulation for structures is fiberglass insulation, sold commercially by Owens Coming (Toledo, Ohio). Although this thermal insulation is very popular, it possesses a relatively low “R” factor and reduced thermal insulating properties as it absorbs moisture. Fiberglass material may also be a health hazard. Likewise, urea-formaldehyde foam has been used for insulating cavities and structures. However, use of that foam was prohibited because of alleged health hazards.
Polyurethane and other petroleum-based foams have been used for many years and have substantially better R factors as compared to fiberglass insulation. However, petroleum-based foams suffer several disadvantages. First, they are flammable and can give off toxic fumes if burned. Second, since they are made from petroleum products, such materials are generally bad for the environment if they are not disposed of properly.
U.S. Pat. No. 5,035,951 discloses swellable materials that protect against overheating, comprising an aqueous mixture of a water soluble alkali metal silicate, a hydrated metal silicate clay, and an inorganic particulate material which, when exposed to flame temperatures, endothermically releases a nonflammable gas. The sodium and potassium silicates utilized in this coating have softening points of 1200 and 1280° F., and flow points of 1545 and 1660° F., respectively. This composition utilizes clay and other materials that give the composition the ability to withstand temperatures up to 3200-3400° F.
What is needed in the art is a foam insulation that possesses a high “R” value for insulation, that is nontoxic, nonflammable, and that is not bad for the environment. The present invention is believed to be an answer to that need.